UNIVERSITY     OK     CALIFORNIA 

AGRICULTURAL  EXPERIMENT  STATION. 
BERKELEY,    CAL. 
K.  W.  HILGARD,  DiRECTOR.  BULLETIN  No.  110. 


THE   STUDY 


OF 


HUMAN  FOODS  ÄND  PRACTICAL  DIETETICS. 


BY    NI.    E.  JAKKA,    PH.B. 


FEBRUARY,  1896. 


•SACRAMENTO: 
A,  j.  JOHNSTON,    :    :    :    :    :    :    Superintendent  state  printing. 

1896. 


Lib. 


\  1^1  u.\ 

^3 

r  •    ■ 

i 

THE   STUDY  OF  HUMAN   FOODS  AND 
PRACTICAL  DIETETICS. 

By  M.  B.  Jaffa. 


[This  bulletin  may  be  considered  as  the  sequel  and  natural  complement  of  Mr.  Jaffa's 
bulletin  on  "The  Cattle  Foods  of  California,"  No.  100,  published  in  1893.  This  latter 
excited  a  great  deal  of  interest  and  is  still  frequently  called  for  by  dairymen  and  others, 
showing  that  it  supplied  needed  Information.  It  would  seem  that  a  similar  discussion 
of  hnman  foods  is  at  least  as  much  called  for  at  a  time  when  not  only  hygienic  questions 
bat  also  that  of  economy  are  forcing  themselves  upon  public  notice.  The  present  paper 
was  originally  written  aiid  delivered  as  a  lecture  to  the  University  Science  A.ssociation, 
exciting  a  good  deal  of  discussion  and  interest  at  the  time ;  with  so  many  subsequent 
applications  for  the  tables  that  the  small  edition  prepared  will  soon  be  exhausted.  While 
not  laying  claim  to  originality  save  in  the  arrangement  of  tables  convenient  for  reference 
and  use  in  the  selection  of  dietaries,  together  with  some  data  supplied  by  recent  work 
done  at  this  Station  in  the  analyses  of  fruits  and  nuts,  it  is  thought  that  this  compact 
and  easily  intelligible  presentation  of  the  subject  of  human  dietaries  will  commend 
itself  to  public  attention,  and  may  help  to  rectif^  some  of  the  incorrect  practices  and 
views  now  so  largely  prevalent  in  respect  to  the  principles  upon  which  human  nutrition 
should  be  based  under  the  varied  conditions  of  modern  life. — E.  W.  IT.] 

The  study  of  human  foods  has  only  recently  begun  to  receive  the 
attention  that  the  importance  of  the  subject  demands.  Up  to  fifty  years 
ago  little  was  known  either  of  the  composition  of  the  human  body  or  of  the 
materials  used  as  food.  Since  that  time  thorough  scientific  investigation 
has  been  inaugurated  and  the  progress  has  been  rapid.  As  is  usually  the 
case  in  all  matters  of  scientific  research,  Germany  took  the  lead,  and  the 
writings  of  Liebig,  first  published  in  1842,  may  be  considered  as  pioneer 
work.  Some  idea  of  the  amount  of  chemical  work  done  in  Europe 
alone  may  be  gained  by  noting  that  the  first  edition  of  Dietrich  and 
Konig's  compilation  of  analyses  of  feeding  stuffs,  published  in  1874,  is 
a  thin  volume  of  100  pages,  while  the  second  edition,  seventeen  years 
later,  is  in  two  volumes  containing  1,400  pages. 

We  are  indebted  chiefly,  for  the  results  we  have  in  this  country,  to 
Professor  Atwater,  Director  of  the  Storrs  (Conn.)  Agricultural  Experi- 
ment Station  and  Special  Agent  of  the  United  States  Department  of 
Agriculture;  and  he  deserves  the  greatest  praise  for  his  persistent  and 
patient  efforts  in  inaugurating  this  kind  of  research  in  the  United 
States. 

When  his  investigations  were  first  undertaken,  and  for  about  tAvelve 
years  subsequently,  most  of  the  funds  required  were  furnished  by  pri- 
vate parties  and  sometimes  by  Professor  Atwater  himself.  This  is  one 
of  the  cases  where  the  persistent  efforts  of  private  parties  have  proved 
so  conclusively  to  the  Government  the  importance  and  necessity  of  the 
work  done,  that  it  has  feit  in  duty  bound  to  financially  help  the  cause. 
Last  year  a  considerable  sum  was  appropriated  to  carry  on  the  work 
outlined  by  Professor  Atwater,  and  he  was  appointed  agent  in  charge, 
It  is  to  be  sincerely  hoped  that  our  Station  will  soon  be  in  a  position  to 
help  in  the  great  movement  which  has  secured  such  a  firm  footing  in 
some  parts  of  the  East. 

298129 


But  110  one  couhtry  can  work  out  these  problems  for  the  world;  there- 
are  important  differenccs  in  each  country — in  environment,  in  habits  of 
food  consumption,  and  in  the  nature  and  composition  of  available  fo<td- 
stuffs — that  need  special  investigation  for  eaeh.  Thus  far,  in  the  United 
States  much  more  work  has  been  done  in  the  line  of  cattle  foods  than 
in  human  foods. 

Jnvestigations  of  cattle  foods  have  been  carried  on  for  about  thirtv 
years,  and  the  results  are  in  practical  use  all  over  the  country.  There 
is  scarcely  a  dairyman  worthy  of  the  name  who  does  not  try  to  feed  his 
cattle  in  a  rational,  scientific,  and  economic  manner.  He  is  guided  in 
his  efforts  by  the  results  of  scientific  investigations  at  the  various  Agri- 
cultural  Experiment  Stations;  in  fact,  all  animal  feeders  are  now  loi)k- 
ing  to  these  stations  for  trustworthy  guidance  in  this  direction,  and 
thus  much  practical  good  has  been  accomplished  in  a  few  years.  The 
dairyman  realizes  that  in  order  to  get  the  greatest  quantity  of  good 
milk  from  his  cows  he  must  give  them  a  sufficient  amount  of  the 
materials  necessary  for  its  production.  He  is  not  actuated  by  motives 
of  philanthropy,  for  he  knows  he  can  thus  get  the  largest  return  for  his 
outlay,  and  that  his  animals  will  do  enough  better  work  to  compensate 
him  for  the  trouble  and  expense. 

Why  can  we  not  look  upon  the  feeding  of  human  beings  in  the  same 
practical  way?  How  long  will  we  continue  to  eat  merely  to  satisfy  our 
hunger — eating  anything  that  comes  in  our  way,  anything  that  pleases 
our  taste,  without  regard  to  special  conditions  or  special  needs?  And 
yet  this  is  what  the  large  majority  of  people  do.  How  many  men  are 
there  in  the  ordinary  walks  of  life  who  give  even  a  passing  thought  to 
the  character  of  food  they  require — whether  more  nitrogenous  or  starchy, 
or,  indeed,  even  as  to  how  much  thCy  need  to  keep  them  in  a  vigorous, 
healthy  condition.  How  many  of  us  who  are  even  in  the  midst  of 
chemical  research,  and  who  dwell  in  an  intellectual  atmosphere,  give 
any  attention  to  the  subject  of  eating,  or  make  any  attempt  to  regulate 
our  diet  according  to  the  scientific  data  at  our  command.  The  causes 
of  this  neglect  are  twofold:  First,  our  natural  conservatism  prompts  us 
to  continue  to  eat  what  we  always  have  eaten;  and  second,  we  are  ignor- 
ant  both  of  the  kinds  and  composition  of  the  food  needed  and  tlie 
required  relative  quantity  of  each. 

Sir  Henry  Thompson,  a  noted  English  pliysician,  says:  "  I  linve  come 
to  the  conclusion  that  more  than  one-half  the  disease  whieh  embitters 
the  middle  and  latter  part  of  life,  is  due  to  avoidable  errors  in  diet, 
*  *  and  that  more  mischief  in  the  form  of  actual  disease,  of  impaired 
vigor,  and  of  shortened  life,  accrues  to  civilized  man  *  *  *  in  En- 
gland and  throughout  Central  Europe  from  erroneous  habits  of  eating 
than  from  the  habitual  use  of  alcoholic  drink,  considerable  as  I  know 
that  evil  to  be." 

But  new  as  the  food  (^uestion  is,  we  certainly  have  ahiady  sufficient 
reliable  data  witli  whicli  to  make  a  beginning,  and  it  is  the  object  of 
this  paper  to  give  a  brief  survey  of  the  subject,  and  to  point  out  to  those 
whose  work  does  not  l)ring  them  iiito  toucli  witli  tliis  line  of  tliouglif.  a 
few  of  the  main  })oiiits  and  simple  rules  of  })ractical  feeding. 

This  paper  is,  then,  presented  to  the  public  with  tlie  liope  that  it  may 
help  to  popularize  the  long-neglected  but  important  subject  of  scientific 
feeding.  All  unnecessary  details  hav(>  been  omittcd  in  order  to  nuike 
the  sul)ject  as  clear  as  possible  to  tliose  to  whom  it   niay  be  nt^w;  and 


—  5  — 

the  tables  have  been  arranged  so  that  they  may  be  most  easily  used  by 
any  who  are  unaccustomed  to  such  work. 

Before  proceeding  with  the  study  of  dietaries  it  may  not  be  out  of 
place  to  give  a  brief  resume  of  the  first  principles,  the  A  B  C's,  as  it 
were,  of  the  subject,  i.  e.,  the  objects  of  feeding — the  chemical  com- 
position  of  the  various  parts  of  the  body;  and  also  the  classes  of  food- 
stuffs,  with  the  offices  the  different  ones  perform  in  the  body. 

OBJECTS    OF    FOOD. 

We  all  know  that  the  young  body,  animal  or  human,  requires  food  to 
supply  the  material  necessary  for  its  growth.  But  beyond  this,  and 
continuing  during  and  past  the  growing  stage,  there  is  a  current 
wearing-out  and  breaking-down  of  all  the  various  tissues  of  the  body. 
This  loss  must  be  supplied  in  order  to  keep  the  animal  in  a  normal, 
healthy  condition.  Not  only  must  the  worn-out  tissue  be  replaced,  but 
the  material,  used  as  fuel  in  producing  the  energy  necessary  for  carrying 
on  all  voluntary  and  involuntary  functions,  must  also  be  supplied.  A 
man  who  is  doing  hard  physical  work  is  using  up  a  great  deal  of  fatty 
tissue,  as  well  as  muscle;  but  a  man  who  is  doing  nothing  (making  no 
voluntary  exertion),  also  experiences  a  loss  of  tissue  through  the  con- 
stant  production  of  the  heat  necessary  for  the  maintenance  of  the 
normal  body  temperature,  and  also  for  the  Performance  of  all  the 
involuntary  functions  of  the.  body.  Hence  we  might  summarize  the 
objects  of  feeding  as  follows: 

1.  To  build  up  and  maintain  the  body  in  its  normal  condition. 

2.  To  serve  as  a  fuel-supply  to  be  consumed  in  the  body,  producing 
heat  to  keep  it  warm,  or  the  energy  (muscular  or  otherwise)  necessary 
for  the  Performance  of  work. 

3.  To  be  stored  for  future  use. 

COMPOSITION   OF   FOODS. 

In  Order  to  see  how  these  objects  may  best  be  carried  out,  we  must 
understand  the  composition  of  these  tissues  that  need  rebuilding,  and 
also  the  composition  of  the  various  foodstuffs  at  our  command.  Viewing 
them  side  by  side  for  the  purpose  of  better  comparison,  we  see,  from  a 
general  analysis,  that  each  is  composed  of  the  same  four  main  ingredi- 
ents — water,  mineral  matters,  nitrogenous  and  non-nitrogenous  material. 

Water. — Water  constitutes  about  two  thirds  of  the  weight  of  the  body, 
and  enters  into  the  composition  of  all  its  tissues  and  fluids.  As  it  does 
not  form  nearly  that  large  a  proportion  of  our  ordinary  cooked  foods, 
we  can  readily  understand  the  necessity  of  its  use  as  a  separate  part  of 
our  diet. 

Mineral  Matters. — The  mineral  matter  comprises  about  5  per  cent  of 
the  body,  and  has  important  functions  to  perform,  such  as  entering  into 
the  formation  of  the  bones  and  teeth,  regulating  the  density  and  taking 
part  in  the  functions  of  the  blood  and  such  other  fluids  of  the  body,  as 
the  bile,  Juices  of  the  stomach,  etc.  In  estimating  food-values,  the 
mineral  or  inorganic  ingredients  are  generally  omitted,  not  on  account 
of  any  lack  of  importance  of  that  portion  of  our  food,  but  for  the  reason 


—  6  — 

that  nearly  all  foods,  no  matter  of  what  description,  contain  a  sufficient 
amount  of  these  sub^tances,  which  comprise,  mainly,  lime,  potash,  and 
phosphoric  acid,  with  varying  quantities  of  sodium,  iron,  magnesia,  sul- 
phuric  acid,  hj'drochloric  acid,  silica,  etc. 

Nitrogenotis,  or  Proteids. — The  nitrogenous  matters  of  the  body,  of  which 
the  major  part  are  called  proteids,  the  only  ones  that  contain  nitrogen, 
are  found  mostly  in  the  niuscle,  gelatinous  part  of  the  bones  and  tendons, 
brain,  nerves,  and  internal  organs;  in  short,  all  the  working  machinery 
of  the  body  is  composed  principally  of  this  important  material.  Simi- 
larly,  in  the  foods,  almost  the  entire  nitrogenous  part  is  called  protein, 
signifying,  by  its  Greek  derivation,  to  take  tirst  place,  ^\'e  receive  the 
protein  from  the  white  of  egg,  the  myosin  of  lean  meat,  casein  of  milk, 
gluten  of  wheat,  gelatinous  parts  of  bones,  tendons,  etc. 

The  necessity  of  this  constituent  in  the  daily  diet  depends  not  only 
upon  its  important  relation  to  such  tissues  as  muscle,  blood,  nerves, 
tendons,  etc.,  but  also  upon  the  fact  that  as  far  as  we  know  no  albu- 
minoid  or  protein  matter  is  formed  in  the  body,  except  by  the  trans- 
formation  of  similar  substances  presented  to  it  from  external  sources.  It 
cannot  be  obtained  by  the  conversion  of  any  other  material. 

The  protein  can  be  changed  into  fats,  and  thus  may  serve  as  fuel  for 
the  body,  hutfats  cannot  replace  protein. 

Non-nitrogenous,  or  Carbohydrates  arid  Fats. — The  non-nitrogeneous 
portions  of  the  solid  constituents  of  the  body  are  principally  fat — the 
material  which  is  consumed  in  the  production  of  heat  and  energy.  The 
source  of  this  substance  in  foodstuffs  is  comprised  in  all  those  portions 
which  are  free  from  nitrogen.  They  are  divided  into  two  main  classes — 
the  carbohydrates  and  fats — and  are  identical  with  those  found  in  the 
body,  with  the  exception  of  starch  and  sugar,  which  aro  not  found  as 
such  in  any  large  amount  in  the  healthy  body. 

The  carbohydrates  comprise  starch,  sugars,  gums,  and  woody  fiber; 
the  latter,  in  the  statement  of  analyses  of  foods,  is  reported  separately, 
while  the  remainder  of  the  aliove  are,  in  order  to  conform  to  the  general 
usage,  chissed  together  under  tlie  head  of  "  nitrogen-free  extract."  The 
gums  play  only  a  secondary  part  as  regards  the  nutritive  value  of  the 
food.  The  carl)ohydratcs  are  mostly  changed  into  fats  and  then  used  as 
fuel;  althougli  it  must  be  remembered  that,  for  the  purpose  of  heat,  fat 
is  worth  2.25  times  as  much  as  carl)ohydrates,  that  is,  1  pound  of  fat  is 
equivalent,  when  used  as  fuel,  to  2.25  pounds  of  starch,  sugar,  etc.  ^\'llen 
there  is  a  deficiency  of  these  Clements  in  tlic  UhmI,  tlic  fat  of  tlic  body  is 
drawn  upon. 

The  fat,  as  might  be  supposed,  varies  morc  tlian  any  otlu-r  substance 
of  the  body,  its  accumulation  being  reguhited  l)y  diet,  niuscular 
exercise,  etc.  Sh'c]),  as  well  as  inactivity,  favors  the  storagc  of  fat,  Mliich 
in  the  average  body  constitutcs  20  \)vv  ccnt  of  the  total  weight. 

If  the  food-supply  is  cut  off,  the  surplus  fat  storcd  U}>  in  the  Itody  is 
drawn  upon  to  keep  the  macliinery  going,  and  if  this  continues  a  oor- 
r(S]»onding  amount  of  ])rotein  is  eonvert(>d  into  fat  and  used  as  such. 
Tlius  we  See  tliat  Ity  having  a  ])roper  })roi)orlion  of  fat  in  our  food  we 
protect  not  only  the  fat  of  the  liody,  but  indirectly,  and  iiiost  iiuiioitant, 
the  protein  of  tlic  muscle  and  blood.  We  receive  our  fat  from  such 
foods  as  the  butter  of  milk,  fat  of  nu-aj,  oil  of  seeds  and   fruits  such  as 


—    7    — 

the  olive,  wax  of  plants,  etc.     The  fats  of  herbaceous  vegetables  have 
less  value  than  those  of  seeds  and  fruits. 

DIGESTIBILITY    OF    FOODS. 

Upon  the  basis  of  the  preceding  we  can  proceed  intelligently  with 
the  next  step,  which  is  to  consider  the  digestibility  of  the  different 
foods.  If  the  total  amoimt  of  each  food  introduced  into  the  body  was 
digestible,  the  whole  subject  of  feeding  would  be  very  much  simplified. 
But,  011  the  contrary,  in  all  foods  there  is  a  certain  portion  of  each 
nutrient,  whether  it  be  protein,  fat,  or  carbohydrate,  which  is  notdigested 
or  assimilated.  A  large  niimber  of  experiments  have  been  made  in 
this  direction,  most  of  them  in  Germany. 

In  Order  to  ascertain  how  much  of  the  food  is  not  digested,  the  food 
is  weighed  and  analyzed  before  consumption,  and  the  weight  and  com- 
position  of  the  excrement  is  also  determined. 

The  difference  between  the  two  analyses  is  taken  as  the  quantity 
digested  or  assimilated.  The  results  so  obtained  are  termed  digestioyi 
co-eßcients,  and  are  only  approximate,  but  in  the  present  state  of  such 
researches,  they  are  the  best  data  available.  Besides  these  direct  experi- 
ments on  the  body,  others  have  been  made  in  the  laboratory  with  success, 
in  which  the  gastric  juice  derived  from  animals  has  been  employed.  This 
cannot  be  so  easily  done  in  the  case  of  man,  as  the  normal  gastric  juice 
from  human  subjects  is  not  ordinarily  obtainable. 

An  animal  can  be  fed  on  one  kind  of  food  for  a  given  time  and  suffer 
no  inconveniences  in  any  way  whatever,  and,  in  all  probability,  would 
relish  it.  Quite  the  contrary  would  be  the  case  with  man.  The  most 
palatable  food  would,  if  fed  alone,  become  exceedingly  distasteful  to 
him  and  tend  to  disarrange  bis  digestive  functions  if  fed  for  five  or  six 
days  in  succession;  and  thus,  at  the  time  when  data  on  the  digestibility 
and  amount  necessary  of  the  food  should  be  obtained,  the  System  of  the 
man  might  be  in  such  a  condition  that  the  data  would  be  unreliable. 
Again,  for  each  food-material  the  digestion  coefficient  may  vary  con- 
siderably  with  different  persons;  still  the  more  nitrogenous  or  easily  solu- 
ble  is  the  food,  the  higher,  as  a  rule,  is  the  digestion  coefficient.  Nearly  all 
of  the  protein  of  ordinary  meat,  fish,  and  milk  is  readily  digested;  that 
of  potatoes,  whole  wheat,  and  rye  flour,  one  fourth  or  even  one  third 
may  not  be  absorbed  by  the  body.  About  95  per  cent  of  the  fats  from 
butter,  milk,  oils,  and  such  foods  is  digestible.  The  vegetable  fats  vary 
from  about  50  to  75  per  cent;  that  is,  the  digestion  coefficient  would  be 
from  50  to  75.  Sugar  is  supposed  to  be  completely  assimilated,  and 
starch  nearly  so  if  not  used  in  excess;  these  two  comprise  the  main 
parts  of  the  carbohydrates.  The  fruits  and  vegetables  contain  the 
bulk  of  the  woody  fiber. 

The  animal  foods  have  in  general  the  advantage  of  the  vegetable,  in 
that  they  contain  more  protein,  and  that  their  protein  is  more  digestible. 
Professor  Atwater  states  that  the  quantity  of  food  digested  appears  to  l)e 
less  affected  by  flavors,  flavoring  materials,  and  food  adjuncts,  and  to 
differ  less  with  different  persons  than  is  commonly  supposed. 

Nutritive  Ratio. — The  different  foods  vary  very  much  in  their  com- 
position;  some,  such  as  peas  and  beans  and  the  meats,  contain  large 
amounts  of  protein  or  muscle-forming  ingredients,  and  very  little  of  the 


—    8    — 

non-nitrogcnous  materials;  others,  as  the  potato,  rice,  and  some  friiits, 
have  chiefly  starchy  matter  associated  with  small  quantities  of  albu- 
minoids;  and  again,  as  in  the  case  of  the  vegetahles  in  general,  we  have 
small  amounts  of  both  carbohydrates  and  nitrogenous  materials. 

The  Proportion  between  the  two  important  elements  of  our  food  is 
termed  the  nutritive  ratio;  or,  in  other  words,  it  is  the  ratio  of  the 
digestible  protein  to  the  sum  of  the  digestible  portions  of  the  remaining 
ingredients  of  the  food.  In  estimating  this  remainder,  the  figiire  denot- 
ing  the  amount  of  fat  is  multiplied  by  2.25,  because  it  has  been  ascer- 
tained  by  experiment,  as  before  stated,  that  about  2.25  times  as  much 
heat  is  developed  by  the  combustion  of  a  pound  of  fat  as  is  by  the  same 
quantity  of  carbohydrates.  This  product  is  added  to  the  weight  of  the 
carbohydrates  and  the  sum  divided  by  the  figure  for  the  protein,  the 
quotient  being  the  nutritive  ratio. 

To  illustrate,  let  us  take  wheat  flour,  the  analysis  of  which  is  as  fol- 
lows:  Water,  12.50  per  Cent;  protein,  8.00  per  Cent;  fat,  1.10  per  cent:  and 
carbohydrates,  77.90  per  cent.  The  fat  percentage,  1.10,  multiplied  ])y 
2.25,  amounts  to  2.48;  this  added  to  the  figure  for  the  carbohydrates, 
77.90,  makes  80.38,  which  divided  by  8,  the  per  cent  of  protein,  gives 
10.05.  Hence,  the  nutritive  ratio  is  1:10;  in  other  words,  there  is  in 
wheat  flour  one  part  of  protein  or  nitrogenous  matter  to  10  parts  of  non- 
nitrogenous  or  starchy  material.  The  ratio  is  "  wide,"  and  termed  a  car- 
bonaceous  one  when  the  amount  of  protein  to  the  remaining  ingredients 
is  small,  as  seen  above.  A  "narrow"  or  nitrogenous  ratio  is  one  where 
the  reverse  is  the  case;  that  is,  the  amount  of  protein  is  large  compared 
to  that  of  the  carbohydrates:  as  1  of  protein  to  about  4  or  5  of  sugar  or 
starchy  matters. 

DIETARIES. 

When  speaking  of  cattle  foods,  the  amount  which  is  daily  necessary 
to  keep  an  animal  in  a  healthy,  satisfied  condition  is  a  ration.  In  dis- 
cussing  human  foods,  the  quantity  required  for  daily  consumption  is 
termed  a  dietary,  although  both  terms  are  in  use.  A  well-balanced  diet 
is  one  in  wliieh  the  protein,  or  flesh-formers,  and  carbohydrates,  or  fat- 
producers,  exist  in  ihv  proper  proportion.  Usually  we  use  foods  or  diets 
unbalanced,  in  that  they  contaiu  too  much  (■arbt)hydrates.  In  other 
words,  we  eat  too  much  starch  and  fatty  foods  and  an  insufficient 
amount  of  nitrogenous  or  flesh-forming  ingredients. 

The  dietary  Standards  at  our  command  have  been  worked  out  liy  \'oit 
in  Cierniany,  Playfair  in  England,  Atwater  in  the  Uniteil  States,  and 
others.  The  daily  average  for  the  (lifiVi-cnt  ingredients  is  altout  one 
quarter  pound  of  protein,  a  third  of  a  jtomul  of  fat,  and  a  little  over  a 
pound  of  carbohydrates,  making  a  nutritive  ratio  of  1:5.8,  with  a  fuel 
value  of  about  ;'>,5()()  cal(U'ies. 

Fiiel  ]'alue.-  By  having  the  analyses  of  tlie  dilTerent  foods  at  our  dis- 
posal,  we  would  be  able  to  calculate  a  considerable  nuinl)er  of  dietaries; 
l)Ut  a  somewhat  simi)ler  method  is  to  use  what  is  ternieil  the  fuel 
value  of  foods.  Tliis,  as  the  namc  im])1ies,  is  the  lieating  power  of  the 
food.  If  we  l»urn  a  ])ie('e  of  fat  it  will  giMierate  a  certnin  amount  of 
lieat,  so  will  a  lump  of  sugar  or  starcli,  or  any  other  food-niaterial. 
If  this  heat  wore  applied  to  water,  it  wouhl  warm  it  to  a  greater  or  less 
extent,  <h']»cii(ling  U])on  Ihc  niiiounl  ol"   heat    sd  free  by  the  coiuhustion 


of  the  material  in  question.  The  unif  of  measurement  of  this  heat  is 
termed  a  calorie.  A  calorie  is  the  amount  of  heat  necessary  to  raise  one 
kilogram  of  water  1*^  centigrade,  or  one  pound  of  water  4°  Fahr.  The 
Units  of  heat,  or  niimber  of  calories,  contained  in  a  given  weight  of  the 
different  food  ingredients,  have  been  very  accurately  ascertained  by  means 
of  the  calorimeter. 

It  would  take  up  too  miich  space  to  describe  in  detail  the  calorimeters 
which  have  been  used  in  the  analyses  of  foods.  In  general,  the  calor- 
imeter consists  of  a  vessel,  bomb  shaped  according  to  the  latest  design, 
about  10  cm.  by  13  cm.;  this  bomb  is  immersed  in  a  vessel  containing 
two  liters  of  water,  which  vessel  is  surrounded  by  an  empty  cylinder, 
enveloped  in  its  turn  by  another  empty  vessel.  As  a  protection  to  these, 
there  is  still  another  cylinder  containing  water;  the  outside  of  this 
cylinder  is  lined  with  a  thick  layer  of  feit.  Hence,  there  is  a  layer  of 
feit,  one  of  water,  and  two  of  air  between  the  calorimetric  apparatus 
proper  and  the  external  air.  The  material  to  be  burned  is  placed  in  a 
platinum  capsule  in  the  "bomb,"  and  ignited  in  presence  of  compressed 
oxygen  by  means  of  an  electric  spark.  A  very  finely  graduated  ther- 
mometer  is  connected  with  the  vessel  containing  the  two  liters  of  water, 
and  the  heat  imparted  to  the  water  and  indicated  by  the  thermometer, 
measures  the  fuel  value  of  the  food-material  burned. 

It  has  been  found  that,  taking  the  ordinary  foods  as  they  are  at  our 

command — 

One  pound  of  protein  yields  1,860  calories. 

One  pound  of  carbohydrates  yields  1,860  calories. 

One  pound  of  fat  yields  4,220  calories. 

That  is,  the  fuel  value  of  fat  is  about  2.25  times  that  of  either  the 
starchy  or  the  nitrogenous  substances,  as  was  stated  when  discussing 
the  nutritive  ratio. 

Now,  if  a  pound  of  fat  is  consumed  by  an  animal  it  becomes  a  heat- 
producer;  in  other  words,  a  slow  combustion  takes  place,  and  the  result 
is  identical,  as  far  as  heat  units  are  concerned,  with  that  obtained  by 
the  calorimeter.  This  has  been  proved  by  means  of  respiration  calor- 
imeters, devised  by  some  German  investigators  in  this  work,  notably 
Drs.  Rubner,  Rosenthal,  and  Pettenkofer,  of  Munich,  and  they  have 
obtained  the  same  figures  for  the  heat  units  in  the  nutrients  of  the  food 
as  those  just  given,  viz.:  1,860  calories  for  protein  and  carbohydrates, 
and  4,220  calories  for  fat.  Several  different  forms  of  respiration  calor- 
imeters have  been  tried  with  varying  success.  The  best  forms  are  those 
designed  by  Rubner  and  Rosenthal. 

Rubner's  respiration  calorimeter  consists  of  a  metal  box  with  double 
walls.  In  the  interior  are  arrangements  for  keeping  an  animal,  as  in 
the  ordinary  respiration  apparatus.  Provision  is  made  for  conducting 
a  current  of  air  through  this  Chamber  and  for  measuring  its  amount 
and  determining  its  composition. 

In  Rubner's  apparatus  the  air  in  the  double  walls  is  allowed  to  expand 
and  contract;  and  these  changes,  as  shown  by  a  manometer  (pressure 
gauge),  are  the  measure  of  the  heat  radiated  from  the  body.  In  this 
case  it  is  the  increase  or  decrease  of  volume  under  constant  pressure. 
In  Rosenthal's  apparatus,  it  is  the  Variation  of  pressure  from  a  constant 
volume. 


—  10  — 

Dietary  Standards. — Rubner,  and  others,  also  found  that  the  fats  and 
carbohydrates  could  replace  each  other  in  any  dietary  in  the  proportions 
of  1  of  fat  to  2.25  of  the  starchy  material,  without  altering  the  food 
value  of  the  diet  or  ration.  This  being  the  case,  we  readily  see  why,  if 
we  know  the  protein  or  nitrogenous  Contents  of  the  dietary  and  the  fuel 
value  in  calories,  we  greatly  simplify  the  calculation,  and  at  the  same 
time  the  detailed  composition  of  the  dietary. 

We  must,  however,  know  the  amount  of  protein  or  albuminoids  that 
is  required,  as  the  fuel  value  of  a  dietary  affords  no  indication  of  the 
Contents  of  this  valuable  and  necessary  element  of  our  food.  But,  know- 
ing  this  and  the  fuel  value,  we  can  choose  from  a  number  of  foods 
dietaries  which  will  be  at  the  same  time  both  nutritious  and  to  our 
taste.  In  Table  I  are  given  some  of  the  dietary  Standards  worked  out 
by  Voit,  Playfair,  and  Atwater.  It  must  not  be  supposed  that  they  are 
absolute,  quite  the  contrary,  but  they  are  the  results  of  researches  up  to 
the  present  time,  and,  as  stated  by  Professor  Atwater,  more  investiga- 
tions  in  this  all-important  question  are  urgently  called  for. 


TABLE  I. 
Dietary  Standards. 


Protein. 


Lbs. 


Ozs. 


Fat. 


Lbs. 


Ozs. 


Carbohydrates. 


Lbs. 


Ozs. 


Fuel 
Value 
(Calo- 
ries). 


Nutri- 
tive 
Ratio. 


1.  Children,  1-2  years  (average) 

2.  Children,  2-6  years  (average) 

3.  Children,  6-15  years  (average)  ... 

4.  Adult  in  füll  health — Playfair... 

5.  Active  lahorers — Play  fair  

6.  Man  at  moderate  work — Voit 

7.  !Man  at  hard  work^Voit 

8.  Man  with  little  physical  exercise 

— Atwater 

9.  Man  with  light  muscular  work— 

Atwater 

10.  Man  with  moderate  work  —  At- 

water  

11.  Man  with  active  work — Atwater. 
IMan  with  hard  work — Atwater.. 

Subsistence  diet— Playfair. 

Average  of  7  dietaries  of  profes- 
sional men,  Eurojie 

Average  of  5  dietaries  of  profes- 
sional men,  United  States. 


12, 
LS. 
14, 

15, 


.06 
.13 
.16 
.26 
.34 
.26 
.32 

.20 

.22 

.28 
.33 
.39 
.13 

.25 

.27 


1.00 
2.00 
2.61 
4.16 
5.44 
4.16 
5.12 

3.20 

3.52 

4.48 
5.28 
6.24 
2.00 

4.00 

4.32 


.08 
.09 
.10 
.11 
.16 
.12 
.22 

.20 

.22 

.28 
.33 
.55 
.03 

.22 

.34 


1.31 
1.41 
1.52 
1.71 
2.56 
1.92 
3.52 

3.20 

3.52 

4.48, 

5.28 

8.80 

.50 

3.52 

5.44 


.16 

.44 

.71 

L17 

1.25 

1.10 

.99 

.66 

.77 

.99 
LIO 
1.43 

.75 

.63 
1.08 


2.61 
7.05 
11.46 
18.72 
20.00 
17.60 
15.84 

10.56 


12.32    2,800 


15.84 
17.60 
18.88 
12.02 

10.08 

17.28 


765 
1,420 
2,040 
3,140 
3,630 
3,055 
3,370 

2,450 


3,520 
4,060 
5,700 
1.760 

2,670 

3,925 


5.6 
5.0 
5.2 
5.5 
4.7 
5.3 
4.7 

5.5 

5.7 

5.8 
5,6 
6.9 
6.3 

4.7 

6.6 


An  inspection  of  the  table  shows,  first,  that,  naturally,  the  more 
physical  work  a  man  does  the  larger  amounts  of  food  he  rei][uires;  and 
secondly,  that  the  American  workman  consumes  more  food  than  eithor  tlie 
English  or  (lerman  laborer.  Tliis  is  best  seen  by  comparing  dietaries 
Nos.  5,  7,  and  12.  Similarly,  from  the  limited  data  a(  liand  it  is  noted 
by  examining  Nos.  14  aiid  15  tliat  the  professional  men  of  iMiropr  do 
not  eat  as  mucli  as  their  American  brethren. 

On  comparing  the  fuel  value  of  the  several  dietaries  in  tliis  table  we 
find  tliat  a  child  of  from  1  to  2  years  of  age  requircs  the  miiiimum  of 
705  calories.  W'licii  it  is  from  2  to  (5  years  old,  the  food  must  have 
nearly  twice  tlie  fuel  value,  or  1,-120  calories;  tli<Mic(>  up  to  15  years  food 


—  li- 
ef 2,040  calories  is  demanded,  while  for  an  adiüt  in  füll  health  the  fuel 
value  must  be  increased  to  3,520  calories. 

A  man  at  hard  work  naturally  requires  the  maximum  amount  of  food, 
whicli,  on  an  average,  must  represent  a  fuel  value  of  5,700  calories. 

Nos.  14  and  15  are  not  really  dietary  Standards,  but,  as  stated,  are  the 
average  of  the  respective  number  of  dietaries  mentioned,  and  are  in- 
serted  in  the  table  for  comparison  only.     In  the  case  of  children,  Nos. 

1,  2,  and  3,  it  will  be  seen  that  the  protein  or  nitrogenous  part  and  the 
carbohydrates  of  the  food  increase  very  rapidly  with  the  age,  while  the 
fat  does  not  vary  materially  between  the  ages  of  2  and  15.  Very 
few  people  realize  "how  much  protein  is  needed  by  the  very  young  child, 
and  great  errors  in  diet  are  made  even  by  those  who  give  the  most  care- 
ful  thought  to  the  proper  training  and  feeding  of  the  young.  When 
the  diet  of  an  Infant  of'  10  to  12  months  old  is  changed  from  one  of 
strictly  milk,  the  child  is  generally  given  for  the  next  four  to  ten 
months  a  diet  composed  mostly  of  starch  (mush,  potato,  bread,  rice, 
sago,  etc.),  with  of  course  some  milk  ;  whereas,  it  not  only  needs  nitroge- 
nous matter,  but  is  better  prepared  to  digest  it.  It  may  be  said  right 
here,  as  no  further  reference  will  be  made  to  the  subject,  that  soup  does 
not  furnish  the  needed  protein,  but  that  some  egg  and  meat  or  the  juice 
of  rare  beef  with  plenty  of  milk,  combined  with  the  cereals  used,  would 
more  nearly  approach  the  Standard. 

The  subsistence  dietary,  No.  13,  amounts  to  very  little  more  than  No. 

2,  that  of  a  child  between  2  and  6  years  old  ;  the  protein  or  nitroge- 
nous matter  being  identical  in  both  cases. 

The  figures  just  given  in  the  table  represent  the  amounts  of  the 
nutrients  actually  contained  in  the  different  dietaries,  but  do  not  give 
any  indication  of  the  total  bulk  of  the  food  eaten. 

In  cattle  feeding  there  has  to  be  a  certain  bulk  of  dry  matter  so  Üiat 
the  animal  may  feel  satisfied  and  the  digestive  processes  go  on  in  a 
normal  manner.  With  man  also,  for  the  same  reasons,  a  certain  bulk 
is  necessary.  Bread,  potatoes,  vegetables,  and  similar  foods  take  the 
place  of  the  coarse  fodders  in  the  cattle  foods. 

The  question  of  rations  for  cattle  is  a  much  simpler  one  in  many 
respects  than  for  man,  for  in  the  latter  case  there  are  many  circum- 
stances  which  militate  against  the  getting  of  reliable  data  on  the  subject. 

Dr.  Rubner  states  that  a  diet  of  bread  and  water  is  more  endurable 
than  one  of  fish,  eggs,  meat,  or  any  other  single  article  of  diet.  In  an 
experiment  with  a  Bavarian,  a  diet  of  bread  and  water  was  fed  for  three 
days.     About  2.5  pouiids  of  bread  were  consumed  per  day. 

In  another  experiment  with  a  medical  student  in  Munich,  beefsteak, 
exceedingly  well  cooked,  was  used  as  the  diet,  but  the  quantity  eaten 
was  less  than  two  pounds  daily.  The  meat,  although  so  well  served, 
became  very  distasteful  even  on  the  second  day. 

Division  and  Composition  of  Foods. — The  human  foods  are  divided 
into  two  main  classes — the  animal  and  vegetable.  The  animal  contains 
chiefly,  with  reference  to  nutrients,  albuminoids  with  more  or  less  of 
fat,  and  are  generally  designated  as  nitrogenous  foods,  while  the  greater 
part  of  the  nutriment  in  vegetable  foods  is  carbohydrates  or  starchy 
materials.  The  exceptions  to  this  are  the  peas  and  beans,  whose  com- 
position includes  about  25  per  cent  of  albuminoids,  and  hence  they 
should  be  classed  as  nitrogenous  foods. 


—  12 


It  must  not  be  forgotten  that  while  in  all  foods  there  is  a  certain  por- 
tion  which  is  not  digestible,  there  is,  in  addition  to  this,  in  the  food- 
materials  as  they  are  found  in  the  market,  notably  in  the  animal  foods, 
considerable  refuse  or  waste  material,  which  varies  froni  about  5  per 
Cent  in  some  of  the  meats  to  as  high  as  50  per  cent,  and  consists  of 
bones,  skin,  etc. 

In  the  vegetable  foods  this  refuse  does  not  amount  to  so  much,  and  in 
the  cereal  part  of  our  diet,  practically  nothing.  In  potatoes  and  cab- 
bage  there  is  about  15  per  cent  of  refuse;  in  squash,  50  per  cent;  in 
turnips,  25  per  cent;  in  apples  and  grapes,  about  25  per  cent.  Table  II 
shows  the  proportion  of  waste  material  in  some  of  our  ordinary  foods 
as  we  buy  them. 

TABLE  II. 

COMPOSITION    OF    DiFFEEENT   FOOD-MaTEKIALS. 

(Atwater) 


Refuse. 

(Bones, 

SheU, 

Skin, 

etc.) 


Edible  Portion. 


Water. 


Nutrients. 


Total. 


Protein. 


Fat. 


Garbo-  I  Mineral 
hydratesi  Malters. 


151 

o  c  s 

a:  3  .— ' 

,    r'a 


Beef— Rib 

Sirloin 

Yeal — Shoulder 

Mutton— Leg 

Loin 

Pork—  Fresh,  Shoulder 

Ham 

Chicken 

Turkey  .. 

Eng  (in  Shell)... 

Fish— Codfish 

Salmon 

Halibut 

Mackerei 

Flounder 

Oj'sters  (in  shell) 

Lobsters 


21.0 
19.5 
17.9 
18.1 
15.8 
14.6 
11.4 
38.2 
32.4 
13.7 
29.9 
35.3 
17.7 
44.8 
66.8 
82.3 
62.1 


38.0 
48.3 
56.7 
50.6 
41.5 
43.0 
36.8 
44.6 
44.7 
63.1 
58.5 
40.6 
61.9 
40.4 
27.2 
15.4 
31.0 


40.8 
32.2 
25.4 
31.3 
42.7 
42.4 
51.8 
17.2 
22.9 
23.2 
11.6 
24.1 
20.4 
15.0 
6.0 
2.3 
6.9 


12.2 
15.0 
16.6 
15.2 
12.6 
13.6 
14.8 
15.1 
16.1 
12.1 
10.6 
14.3 
15.1 
10.0 
5.2 
LI 
5.5 


27.9 

16.4 

7.9 

15.6 

29.5 

28.0 

34.6 

12 

5.9 

10.2 

.2 

8.8 

4.4 

4.3 

.3 

.2 

'.7 


.6 
.1 


.7 

1,405 

.8 

970 

.9 

640 

.7 

935 

.6 

1,480 

.8 

1,435 

2.4 

1,735 

.9 

330 

.9 

550 

.9 

655 

.8 

205 

1.0 

6;« 

.9 

465 

.7 

365 

.5 

110 

.4 

40 

.6 

135 

The  abovc  table  shows  groat  variations  in  tlie  refuse  of  the  different 
foods  represented.  In  beef  the  waste  is  about  20  per  cent,  very  little 
morc  than  one  lialf  that  of  turkey,  and  not  far  from  five  eighths  the 
amount  givcn  for  chicken.  This  is  important  in  more  ways  than  one, 
because  while  the  pricc  of  chicken  is  oftcn  higher  than  that  oi  beef,  there 
is  more  nourishment  in  the  beef,  owing  to  its  larger  contents  of  fat,  and 
also,  as  just  stated,  because  the  waste  or  refuse  in  beef  is  only  about  one 
half  that  of  chicken.  Thesame  can  ho  said  of  turkey.  Mutton  eontains 
less  Avaste  material  than  l)eef,  and  ])()rk  sliows  a  lower  pert'entage  in  this 
respect  than  mutton. 

Of  the  meats  mentioned  in  the  tal)le,  the  protiMU  contents  do  not  show 
as  wide  differences  as  do  the  fats;  the  ränge  for  the  ])r()tein  beiug  from 
12  to  1(),  while  that  of  the  fat  varies  all  the  way  from  20.5  per  cent  in 
mutton  (loin)  to  1.2  in  chicken.  Hcncc,  we  see  that  chicken  would  l)e 
ex('ell('nt  for  jtersons  wishing  a  nitrogenous  aniinal-food  associated  with 
the  minimum  fat. 


—  13  — 

Among  the  fishes  the  least  waste  material  is  found  in  the  halibiit,  with 
17.70  per  cent,  and  the  greatest  in  the  flounder/which  contains  66.8  per 
Cent;  yet  the  same  price  woukl  probably  have  to  be  paid  for  each.  The 
average  protein  content  in  the  fishes  is  somewhat  lower  than  the  cor- 
responding  average  for  the  meats.  The  amount  of  fat  found  in  fish  is 
small,  salmon,  with  8.8,  having  the  maximum,  and  flounder,  with  .3  per 
Cent,  the  minimum.  The  shell  fish  all  have  high  percentages  of  waste 
material. 

Table  II  is  very  interesting  and  quite  important  in  its  way,  both  as 
regards  food  value  and  food  economy.  It  is  not,  however,  in  a  convenient 
form  for  the  calculation  of  dietaries;  a  difficulty  overcome  by  Tables  III 
and  IV,  which,  respectively,  show  the  amounts  in  ounces  of  nutrients 
per  pound,  and  parts  of  an  ounce  per  ounce,  of  the  different  foods  repre- 
sented.  In  the  tables  the  data  given  for  the  friiits  and  nuts  have  been 
estimatecl  from  analyses  made  by  Mr.  George  E.  Colby  of  this  Station, 
that  for  California  flour  and  bread  from  analyses  of  my  own,  while  the 
figures  for  the  remaining  foods  were  calculated  from  data  published  by 
Professor  Atwater. 

Having  these  tables  before  us,  the  making  up  of  dietaries  is  a  very  simple 
matter.  It  should  be  said  that  in  these  tables  the  figures  for  Nos.  1  to 
15,  inclusive,  include  the  waste;  while  for  the  remainder  the  edible  por- 
tion  only  is  represented. 


—  14  — 


TABLE   III. 
Showing  Amoünts,  in  Oüncbs,  of  Nütriexts  IX  OxK  PouND  or  DiFFEREST  Foods. 


Edible  Portion. 


Water. 


Nutrients  (Ounces). 


Total.     Protein. 


2-  o  -< 

Carbo-  1  Mineral     ^Ss! 

hydrates,  Maliers.,    o5.= 


1.  Beef— Roast  Rib. 6.08 

2.  Sirloin I  7.73 

3.  Mutton— Leg 8.10 

4.  Loin 6.64 

5.  Veal,  Shoulder 9.07 

6.  Pork—P^esh,  Shoulder 6.88 

7.  Ham 5.89 

8.  Chicken 7.14 

9.  Turkey i  7.15 

10.  Eggs  (in  Shell) 10.10 

n.  Fish— Codfish ;  9.28 

12.  Salmon 6.50 

13.  Halibut-- 9.90 

14.  MackereL. .|  0.46 

15.  Flounder 4.34 

16.  Oysters I  1.3.93 

17.  Grab 12.34 

18.  Sausage,  Bologna.. 9.98 

19.  Cheese—P\ül  Cream '  4.84 

20.  Skim  Milk 6.61 

21.  Milk 13.92 

22.  Butter '  1.68 

23.  Wheat  Flour  (California). ..|  2.00 

24.  Graham  Flour  (California)  .i  1.94 

25.  Oatnieal i  1.22 

26.  Cornineal j  2.40 

27.  Rice '  1.98 

28.  Peas  (dried) i  1.97 

29.  Beans  (dried) i  2.02 

30.  Potatoes— "Irish" i  12.62 

31.  Sweet 11.38 

32.  Garrots 14.18 

33.  Onions 14.00 

34.  Green  Peas 12.50 

35.  String  Beans.. j  13.95 

36.  Green  Gorn 13.01 

37.  Tomatoes 15.36 

38.  Cabbage ....!  14.48 

39.  Sugar .32 

40.  Bread  (California) |  5.17 

41.  Apples  (California) 13.31 

42.  Oranges  (California).. 14.13 

43.  Prunes(all)  (California) 12.83 

44.  Apricots  (California) 13.61 

45.  Figs  (California)... 12.66 

46.  Grapes  (California) 12.82 

47.  Olives  (California) 9.28 

48.  Walnut.s  (Culil'ornia) .45 

49.  Aliiionds  (California) i  .85 

50.  Peanuts 1.20 


1,405 

970 

935 

1,480 

640 

1,4.35 

1,735 

330 

550 

655 

205 

635 

465 

365 

110 

230 

415 

1,015 

2,070 

1,165 

325 

3,615 

1.627 

1,650 

1,850 

1,645 

1,630 

1,565 

1,615 

375 

530 

200 

225 

405 

235 

345 

80 

155 

1,820 

1,280 

315 

219 

371 

280 

390 

372 

1,404 

3,230 

3,060 

2,619 


—  15  — 


TABLE  IV. 

Showing  Amoünts,  in  Parts  of  an  Ounce,  of  Nutribnts  in  One  Oünce  of 

DiFFBRENT    FOODS. 


Edible  Portion. 

Nutrients  (Ounces). 

Fuel 

Water. 

Value 

of  One 

Carbo- 

Mineral 

Ouiice 

Total. 

Protein. 

Fat. 

hydrates 

Matters. 

1   Beef— Roast  Rib 

.380 
.480 
.506 

.408 
.322 
.313 

.122 
.150 
.150 

.279 
.164 
.156 

.007 
.008 
.007 

88 

2               Sirloin 

61 

3.  Mutton— Leg -. 

58 

4                     Loin 

.415 
.567 

.427 
.254 

.126 
.166 

.295 
.079 



.006  1 
.009 

93 

5.  Veal— Shoulder  .- 1 

16 

6.  Pork— Fresh,  Shoulder , 

.430 

.424 

.136 

.280 

.008 

90 

7.               Harn 

.368 

.518 

.148 

.346 

_  ._ 

.024 

108 

8.  Chicken 

.446 

.172 

.151 

.012 

.009 

21 

9.  Turkev 

.447 

.229 

.161 

.059 

.009 

34 

10.  Eggs  (in  Shell) — . 

.738 

.262 

.149 

.105 

.008 

45 

11    Fish— Codfish           

.585 
.406 
.614 
.404 

.116 
.241 
.204 
.150 

.106 
.143 
.151 
.100 

.002 
.088 
.044 
.043 

.048 
.010 
.009 
.007 

13 

12               Salmon                    

40 

13.               Halibut        

29 

14.              Mackerel 

22 

15.               Flounder 

.272 
.871 
.771 
.624 

.060 
.129 
.229 
.376 

.052 
.060 
.178 

.188 

.003 
.012 
.020 
.158, 

.om 

"".Ö37" 

.005 
.020 
.031 

.030 

7 

16   Ovsters                   

14 

17.  Grab      . 

26 

18.  Sausage— Bologna.- 

63 

19.  Milk 

.870 

.130 

.036 

t:o47 

.007 

20 

20.  Cheese— Füll  Cream 

.302 

.698 

.283 

.355 

'  .018 

.042 

129 

21.                   Skim  Milk 

.413 

.587 

.384 

.068 

.089 

.046 

73 

22.  Butter     

.105 
.125 
.121 
.076 
.150 

.895 
.875 
.879 
.924 
.850 

.010 
.080 
.085 
.151 
.092 

.850 
.011 
.019 
.071 
.038 

.005 
.779 
.758 
.682 
.706 

.030 
.005 
.015 
.020 
.014 

226 

23   Wheat  Flour                   . .... 

102 

24    r4raham  Flour 

103 

25   Oatmeal                       -. 

106 

26.  Cornmeal - 

103 

27.  Rice 

.124 

.876 

.074 

.004 

.794 

.004 

102 

28.  Peas  (dried) 

.123 

.877 

.267 

.017 

.564 

.029 

98 

29.  Beans  (dried) 

.126 

.874 

.231 

.020 

.592 

.031 

101 

30.  Potatoes-"Irish  " 

.789 

.211 

.021 

.001 

.179 

.010 

23 

31.                     Sweet 

.711 

.886 

.289 
.114 

.015 
.011 

.004 
.004 

.260 
.089 

.010 
.010 

33 

32.  Carrots 

13 

33.  Onions 

.875 

.125 

.014 

.003 

.102 

.006 

14 

34.  Green  Peas 

.781 

.219 

.040 

.006 

.016 

.009 

25 

35.  String  Beans 

.872 

.128 

.022 

.004 

.094 

.008 

15 

36.  Green  Corn 

.813 

.187 

.028 

.011 

..i/.(Ä 

.006 

22 

37.  Tomatoes 

.960 

.040 

.008 

.004 

.025 

.003 

5 

38.  Cabbage 

.905 

.095 

.024 

.004 

.053 

.014 

10 

39.  Sugar 

40.  Bread 

.020 

.980 

.978 

.002 

114 

.323 
.832 
.880 
.800 

.677 

.168 

.120 

'       .200 

.064 
.002 
.008 

.003 

.017 
.004 

.587 
.159 

.009 
.003 

"".ÖÖ5" 

80 

41.  Anüles     .  

20 

42    Oransres 

.112 

.187 

14 

43.  Prunes(all) 

23 

44.  Apricots 

45.  Figs... 

.850 

.150 

.010 

.135 

.005 

18 

.790 

1        .210 

.015 

.1 

89 

.006 

24 

46.  Grapes 

.800 

.200 

.013 

.1 

82 

.005 

23 

47.  Olives 

.580 

.420 

1        .011 

.276 

.116 

.017 

88 

48   Walnuts      .. 

1       .025 
.053 
.080 

.975 
.947 
.920 

i        .143 
.176 
.280 

.659 
.562 
.400 

.163 
.191 
.230 

.010 
.018 
.020 

202 

49    Alnionds          .           . 

191 

50.  Peanuts..  

164 

To  illustrate  the  method  of  forming  a  dietary,  any  of  the  Standards 
mentioned  in  Table  I  could  be  used.  An  excellent  one  is  No.  10  as 
adopted. by  Prof.  Atwater,  for  a  man  at  moderate  work,  deduced  from 
extensive  comparisons  of  many  dietaries. 

The  Standard  is  .28  pounds  of  protein,  or  flesh-forming  ingredients,  .28 


—  IG 


poiinds  of  fat,  and  .99  poiinds  of  carbohydrates  or  starchy  material, 
with  a  fuel  value  of  3,500  calories  ;  or  expressed  in  oiinces,  4.48  oiinces  of 
protein,  4.48  ounces  of  fat,  and  15.84  ounces  of  carbohydrates. 

Suppose  we  have  mutton,  salmon,  potatoes,  butter,  bread,  and  graham 
flour  to  choose  from.  The  first  thing  to  do  is  to  glance  at  the  composi- 
tion  of  these  materials  in  the  tables,  and  to  make  a  rough  estimate  at 
the  amounts,  in  pounds  or  ounces,  of  each  needed,  bearing  in  mind  the 
usual  proportions,  approximately,  of  such  things  consumed  in  the  ordi- 
nary  household. 

A  little  practice  will  insure  an  estimate  not  very  far  from  the  correct 
amount.  The  next  step  is  to  calculate  the  proportion  of  the  different 
ingredients  in  the  quantities  estimated  and  compare  them  with  the 
Standard  adopted,  and  to  make  such  corrections  in  the  original  estimate 
as  the  comparison  shows  to  be  necessary. 

To  return  to  our  proposed  dietary,  we  will  suppose  that  we  can  eat  8 
ounces  of  mutton  (loin).  Turning  to  Table  IV  we  find  mutton  (loin) 
numbered  4,  and  we  multiply  by  8  the  figures  given  for  one  ounce,  and 
write  them  down.  After  doing  the  same  for  the  other  articles,  we  have 
the  füllowing  little  table: 


No.  in 
Table. 

Am't  Used. 
Ounces. 

Material. 

Protein. 

Fat. 

Carbohy- 
drates. 

Fuel 
Value. 

4 

12 

8 
8 
3 
18 
1.8 
8 

Mutton  

Salmon 

1.01 
1.14 
0.26 
1.16 
0.02 
0.17 

2.36 
0.70 
0.06 
0.30 
1.53 
O.Ol 

2.28 

10.56 
O.Ol 
1.43 

740 

318 

24 
40 

Graham  Flour 

Bread.                ..        

309 
1,440 

407 

22 

Butter 

30 

Potatoes 

1S8 

46.8 

3.76 

4.96 

14.28  : 

3,402 

The  above  figures  show  us  that  the  protein  is  lacking  in  the  dietary, 
also  that  the  fuel  value  is  slightly  below  the  Standard.  To  remedy  this 
defect  we  add  some  one  article  specially  rieh  in  protein;  suppose  we 
take  about  lg  ounces  of  skim-milk  cheese  (No.  21  in  Table  IV).  Cal- 
culating  this  out  for  the  different  nutrients,  and  adding  to  the  above 
we  have — 


Protein. 


Fat. 


Carbohy-  j    Fuel 
drates.       Value. 


No.  21 — IJ^  ounces  skim-milk  cheese 
Original  dietary 

Completed  dietary 


0.72 
3.76 


0.13 

4.96 


0.17 
14.28 


135 
3,402 


4.48 


5.09 


14.45 


3,537 


Whicli  is  practically  identical  with  our  Standard  as  regards  prutein  and 
fuel  value.  This  is  a  good  Illustration  of  the  fact  that  fat  and  carbohy- 
drates can  replace  each  other  in  any  dietary  or  ration  in  tlie  proportion 
of  1  of  tlie  fonner  to  2.25  of  the  latter  and  not  alter  its  fuel  value.  Our 
Standard  ealls  for  4.48  ounces  of  fat;  we  have  5.09.  TIr-  dil'fi'renee,  O.tll, 
multiplied  by  2.25  amounts  to  1.37,  whieh  almost  equals  the  differenoe 
(1.89)  between  15.84,  the  figure  named  for  earlioliydratcs  in  our  Stand- 
ard, and  14. 15,  the  quantity  given  in  our  assuined  dietary. 

For  a  second  dietary  supjjose  we  take  sirloin  steak,  butter,  milk,  pota- 
toes, and  bread.     Proeeeding  as  before,  we  have — 


17  — 


No. 


2 
22 
19 
30 
40 


Am't  Used. 
Ounces. 


14 

2 
28 
16 
16 


76 


Material. 


Steak... 
Butter .  - 
Milk-.-. 
Potatoes 
Bread  .. 


Protein. 


2.10 
.02 
.99 
.34 

1.03 


4.48 


Fat. 


2.33 
1.70 
1.12 


Carbohy- 
drates. 


.27 


5.42 


.02 
1.28 
2.86 
9.39 


13.55 


Fuel 
Vftlue. 


854 
452 
570 
375 
1,2>;0 


3,531 


This  happens  to  be  a  well-balanced  dietary;  that  is,  one  in  which  the 
nitrogenous  and  non-nitrogenous  materials  are  in  the  proper  proportions. 

As  another  example,  let  us  take  oatmeal,  bread,  eggs,  sweet  potatoes, 
butter,  sugar,  chicken,  and  rice: 


Number 

Amount 

in 

Used. 

Table. 

Guuees. 

25 

4 

40 

16 

10 

4 

31 

8 

22 

3 

39 

3 

8 

8 

27 

2 

48 

Material. 


Total  Nu- 
trieuts. 


Protein. 


Fat. 


Carbo- 
hydrates. 


Fuel 

Value. 
Calories. 


Oatmeal 

Bread 

Eggs.. - 

Sweet  Potatoes 

Butter 

Sugar --  

Chicken 

Rice 


3.68 
10.83 
.93 
2.31 
2.69 
2.94 
1.30 
1.75 


26.43 


.64 

1.03 
.48 
.12 
.03 


1.21 
.15 

3.66 


.32 

.27 

.41 

.03 

2.55 


.09 
.01 


3.68 


2.72 
9.39 


2.08 

.01 

2.93 


1.59 

18.72 


460 
1,280 
164 
265 
678 
342 
165 
204 

3,558 


This  is  a  dietary  with  about  the  right  caloric  value,  but  is  lacking  in 
the  muscle-forming  element,  as  seen  by  the  low  figure  for  protein.  Yet 
it  is  not  by  any  means  an  uncommon  one,  and  most  people  woiüd  con- 
sider  themselves  well  fed  on  it.  The  lack  of  protein  could  be  very 
easily  remedied  by  substituting  beans  for  the  rice,  as  this  change  would 
increase  the  nitrogenous  element,  and,  at  the  same  time,  decrease  the 
amount  of  starch.  If  beans  are  not  relished,  and  rice  is  preferred  with 
chicken,  the  same  result  may  be  obtained  by  reducing  the  amount  of 
sweet  potato  to  one  half,  and  in  the  place  of  it  substituting  a  concen- 
trated  soup  of  dried  peas.  Thus,  in  many  ways  could  this  incorrect 
dietary  (according  to  our  Standard)  be  regulated,  without  making  any 
very  radical  change. 

In  Order  to  show  that  it  is  not  necessary  to  have  any  great  variety  to 
get  the  proper  proportions,  let  us  compare  the  two  foUowing  lists  of 
foods,  given' by  Atwater.  Suppose  one  man  eats  in  a  single  day,  of 
steak,  13  ounces;  butter,  3  ounces;  potatoes,  6  ounces;  and  bread,  22 
ounces.  This  constitutes  a  well-balanced  dietary.  But  the  man  who 
takes  as  his  dietary  pork  chops,  8  ounces;  liver,  8  ounces;  one  egg; 
butter,  3  ounces;  milk,  one  cup;  potatoes,  12  ounces;  turnips,  4  ounces; 
corn,  4  ounces;  oatmeal,  1  ounce;  rice,  1  ounce;  wheat  flour,  4  ounces; 
graham  flour,  2  ounces;  and  sugar,  3  ounces,  would  have  a  dietary  no 
better  in  any  way,  as  they  both  contain  the  same  amount  of  protein, 
4.48  ounces,  with  3,500  calories;  but  the  latter  might  prove  more  pleasing 
to  the  palate,  which  is  worth  considering.  At  the  same  time,  it  might 
also  prove  more  expensive,  or  harder  on  the  stomach — points  which 
must  not  be  lost  sight  of.     One  of  our  Berkeley  students  is  living  on  a 


—  18 


small  loaf  of  bread,  a  pound  of  steak,  and  foiir  oiinces  of  biittor  per  day. 
This  is  a  meager  dietary,  thoiigh  seemingly  like  the  one  just  called  cor- 
rect;  but  the  first  diet  had  potatoes  in  addition,  and  probably  more 
bread.     The  composition  of   his  diet  is  as  follows: 


No.  in 
Table. 

Am't  Used. 
Ounces. 

Material. 

Protein. 

Fat. 

Carbo- 
hydrates. 

Fuel 
Value. 

2 

16 

16 

4 

Steak 

Bread 

Butter .                     

2.40 

1.03 

.04 

2.62 

.27 
3.40 

970 

40 
22 

9.39 
.02 

1,280 
904 

36 

3.47 

6.29 

9.41 

3,154 

The  subsistence  dietary,  No.  13  in  Table  I,  would  consist  of  about  18 
ounces  of  bread  and  6  of  meat,  as  follows: 


Protein. 


Fat. 


Carbo-    j     Fuel 
hydrates.     Value. 


18  ounces  bread 

1.16 

.90 

..30 ; 

.96    .. 

10.56 

1,440 
360 

6  ounces  meat.   ... ..  _. 

2.06 

1.26 

10.56 

1,800 

The  army  ration  of  the  United  States  is  a  good  illustration  of  the  fact 
that  although  several  of  the  foods  seeni  to  have  the  same  composition 
they  cannot  be  used  as  Substitutes  for  each  other.  For  instance,  the  meat 
ration  consists  of  22  ounces  salt  beef,  or  12  of  salt  pork  or  bacon,  or  12 
of  corned  beef  (fresh.or  canned),  or  20  of  fresh  beef,  or  14  of  dried  lish,  or 
18  of  pickled  fish.  The  caloric  value  of  these  meats  vary  greatly,  that  ^ 
of  20  ounces  fresh  beef  being  1,700  with  8.16  ounces  of  p^otein,  while  12./  > 
ounces  corned  beef  has  only  1,200  calories  with  about  5.5  ounces  of  p«)v 
^eirtr.  The  same  may  be  said  of  the  cereal  part  of  the  ration,  thus  prov- 
ing  that  these  materials  connected  by  "  or  "  are  not  always  equivalents. 

The  foUowing  is  an  example  of  a  strictly  vegetable  diet: 


l^ 


No.  in 
Table. 

Am't  Used. 
Ounces. 

Material. 

Protein. 

Fat. 

Carbohy- 
drates. 

Fuel 
Value. 

29 

5 
16 

4 
18 

4 

4 

l?eans  _ 

1.16 
.34 
.12 

1.16 
.30 
.61 

.10 
.02 
.05 
.30 

m 

.28 

2.96 
2.86 
.57 
10.56 
3.18 
2  73 

505 

30 

Potatoes  

375 

36 

(Uirn 

88 

40 

27 

Bread 

Rice - - 

1,440 
408 

25 

üatmeal 

424 

51 

3.69 

.77 

22.86 

3,240 

Tliis  dietary,  wliile  fully  \\\)  to  the  averago  in  aniount  of  food-material, 
is  deficient  in  protein  and  fuel  value,  thus  showing  that  it  would  be  a 
somewhat  diflicult  matter  to  obtain  the  proper  amouni  of  protein  aiul 
the  right  caloric  value  from  a  strictly  vegetable  diet.  It  luust  not  ))e  lost 
sight  of  that  not  only  is  the  })rotein  low,  but  that  tlie  amount  i)resent 
would  not  be  equal  in  nutritive  value  to  the  same  quantity  derived  from 
animal  foods,  owing  to  the  higlier  digestion  coeflicient  of  protein  i)oss(>ssed 
liy  aiiimal  foods.     Thelackof  iirolciii  or  iilbuiuinoids  nnd  f;i(  in  1heal)ove 


—  19  — 

ration  could  be  remediecl  by  the  use  of  nuts,  which  are  rieh  in  both  these 
ingredients. 

Caution,  however,  must  be  used  when  nuts  constitute  part  of  the  die- 
tary,  because  of  the  concentrated  form  in  which  the  nutrients  are  found 
in  these  food  materials. 

The  riebest  of  the  nuts  represented  in  the  table,  with  respeet  to  protein, 
is  the  peanut  (No.  49),  which  is  analogous,  botanieally,  to  the  bean. 
It  does  not  eontain  as  much  fat  as  either  the  wahiut  or  almond,  but 
has  the  great  advantage  of  being  much  cheaper  in  priee. 

It  will  be  seen  by  examining  the  data  given  for  fresh  fruits  that  it 
would  require  a  very  large  bulk  and  amount  of  these  artieles  of  food  to 
yield  a  suffieient  proportion  of  nutrients.  Dried  fruits  eontain  about 
three  times  the  pereentage  of  nutrients  that  are  found  in  fresh  fruits, 
and  are  therefore  more  available  in  the  eonstruetion  of  dietaries. 

Many  more  dietaries  could  be  calculated  from  the  tables,  but  the  few 
examples  are  suffieient  to  give  an  idea  of  the  method  to  be  employed  by 
any  who  intend  to  make  use  of  them  in  properly  regulating  either  their 
own  diet  or  that  of  others. 

A  careful  study  of  the  tables  is  reeommended  to  those  who  appreeiate 
the  importanee  of  the  subjeet,  both  from  the  nutritive  and  the  economic 
Standpoint,  Of  course  individual  tastes  and  idiosyncrasies  must  be  con- 
sidered  in  this  conneetion,  as  it  will  not  do  to  override  these  for  the  sake 
of  eonforming  to  any  preconeeived  ideas. 

It  must  never  be  forgotten  that  while  the  nearest  approaeh  to  a  nor- 
mal dietary  as  expressed  by  the  above  data  should  be  aimed  at,  it  by  no 
means  follows  that  a  dietary  eorrectly  proportioned  aecording  to  the 
above  data  can  be  suecessfully  used  in  every  partieular  case. 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 


AN  INITIAL  FINE  OF  25  CENTS 

WILL  BE  ASSESSED  FOR  FAILURE  TO  RETURN 
THIS  BOOK  ON  THE  DATE  DUE.  THE  PENALTY 
WILL  INCREASE  TO  SO  CENTS  ON  THE  FOURTH 
DAY  AND  TO  $1.00  ON  THE  SEVENTH  DAY 
OVERDUE. 


NOV 


tt^r^s 


jj^^  dQ  1954 


OCT  ^  ■'  ^^5^4 


OCT  0 1 1997 


LD21-100m-7.'33 


ili',,,';;,  BERKELEY  LIBRARIES 


CGSbl0aE3t, 


UNIVERSITY  OF  CAIvIFORNIA  IvIBRARY 


